Despite being the largest pieces of
ice on Earth, it also creates the larges and most numerous land-forms
due to erosion. As a Glacier moves across a body of water, it
also drags the minerals and materials that come in its way underneath.
Over time, the movement will start to erode whatever is underneah,
and in turn create a new land-form.

Common all over the world, glaciated valleys are probably
the most readily visible glacial landform. Similar to fiords,
they are trough-shaped, often with steep vertical cliffs where
entire mountainsides were removed by glacial erosion. One of
the most striking examples of glaciated valleys can be seen in
Yosemite National Park, where glaciers literally sheared away
mountainsides, creating deep valleys with vertical walls.

A Hang Valley in Yellowstone National
Park

Fiords are long, narrow coastal valleys that were originally
carved out by glaciers. Steep sides and rounded bottoms give
them a trough-like appearance. Because the glacier has eroded
the land surface below sea level, now that the glaciers are gone,
sea water covers the valley floor.